1. Technical Field
The disclosure relates in general to a semiconductor structure and more particularly to a semiconductor device of LDMOS, EDMOS, or FDMOS, etc.
2. Description of the Related Art
In the semiconductor technology, the feature size of the semiconductor structure has been reduced. In the meantime, the rate, the efficiency, the density and the cost per integrated circuit unit have been improved.
For example, many methods have been proposed for increasing a breakdown voltage (BVD) of a semiconductor structure such as a lateral double diffused metal-oxide-semiconductor field-effect transistor (LDMOS), an extended drain metal-oxide-semiconductor field-effect transistor (EDMOS) or a field drift metal-oxide-semiconductor field-effect transistor (FDMOS) and so on. However, an on-state resistance (Ron) of the semiconductor structure would be increased due to the conventional methods. Therefore, the semiconductor structure could not obtain a trade off between the BVD and the Ron for obtaining a desired small figure of merit (FOM=Ron/BVD).